MAF and TPS testing help

[Boonie Buster]

'96 Tacoma 2.7L 3RZ

What is the best/easiest way to test if the MAF or TPS is bad? Any methods or things to look for? OR, if it's even those that are the problem.

I'm an electrical dummy, but my papa is lightyears ahead of my in the electrical department so he could look into it as well.

It's been running rough and hesitating to accelerate. It's a little scary being on a steep hill and trying to give it gas and it's doing nothing but bog down and not go! :looser:

I just replaced the spark plugs and cap/rotor and it now runs worse than it did before. I will try disconnecting the battery maybe and "resetting" the brain.... :eeek:

Thanks.

Let me know if i'm leaving out important details.:redneck:

Oh, Boobies.

 

[zukkev]

Seeings it runs worse now, I'd look and make sure you didn't cross a wire...Or accidently hit the electrode of a plug on something, closing the gap...
As for testing the MAF/TPS, best bet is with a lab scope of some sort, glitches can happen sooo fast a simple DVOM will not catch it...

 

[Boonie Buster]

That's very possible kev, I'll double check that stuff first. I might just get new plug wires as well, i'm not sure how old they are...

EDIT: Even before the new plugs/cap/rotor it was running rought though, but i some how managed to make it worse, Midas Touch. :booo:

 

[TreeClimber]

Just for kicks and giggles, have you checked to see if it's a clogged cat convertor?

 

[Boonie Buster]

Just for kicks and giggles, have you checked to see if it's a clogged cat convertor?

No, the problem arose on my last trip and i haven't dug into it much yet, but it's a possibility, 200k miles and it's probably the stock cat. :redneck: It probably has SOME buildup. :haha:

Oh, and the stock manifold has a nice crack in it. Prolly helping to confuse the O2 sensor... :awesomework: :haha:

 

[Boonie Buster]

So, I cleaned the MAF sensor, Thottle Body, and intake all the way back to the head.

It def. made an improvement in runability, but still has a slight hesitation when accelerating. We checked the TPS and it seemed to be working properly, we did an Ohms test (please correct my improper electrical jargon if it's wrong) while cycling the throttle watching the difference in voltage as the throttle was opened, it seemed to be doing as expected.

Maybe a clogged fuel filter? :eeek: It still could maybe be the TPS is causing it, I just don't know... :booo:

EDIT: The cat has been replaced recently.

 

[Rix]

WHAT KINDA PLUGS AND WIRES?
Any codes stored?

 

[Boonie Buster]

WHAT KINDA PLUGS AND WIRES?
Any codes stored?

OEM wires, I just put in NGK plugs two weeks ago along with a new cap and rotor.

It had a CEL but i dont have a code reader to know what it was.

It came on while climbing blewett pass. I disconnected the battery stayed off for a while, during hill climbs wheeling in the liberty area it would hesitate when i went to start from a stop on a steep incline, resulting in scary situations of looking down a hillside. :eeek: Later the next day while climbing stevens pass it came back on, it felt like it had less power than normal for a tall geared truck on 32's and a motorcycle and gear loaded up. :redneck:

 

[Toyotanut]

Run down to an Auto Zone or Oreilys and get your truck scanned.